1. Field of the Invention
This invention relates to an automatic musical accompaniment playing system for use in an electronic musical instrument which can automatically play an accompaniment such as a rhythmic chord and a melodic chord (an arpeggio).
2. Prior Art
There has been proposed an electronic musical instrument which has an automatic musical accompaniment playing system capable of automatically playing an accompaniment such as a rhythmic chord and a melodic chord (an arpeggio) based on a chord determined by a depressed key or keys on a keyboard. The rhythmic chord is played by intermittently generating all constituent tones of the determined chord at timing determined by a selected rhythm, as shown, for example, in FIG. 1. The melodic chord is played by selectively generating one or more constituent tones of the chord in the order determined by a selected rhythm, as shown, for example, in FIG. 2.
Such automatic accompaniment system generally operates in synchronization with an an auto rhythm system incorporated in the electronic musical instrument, as disclosed, for example, in U.S. Pat. No. 4,433,601. The generation of rhythm pattern is controlled by the performer, and the start and stop of operation of the auto rhythm system is also controlled by the performer. With the conventional automatic accompaniment system, however, a tone color (i.e., a voice or a timbre) of the accompaniment has not been changed in eesponse to such change of operation of the auto rhythm system, so that it has been possible that the accompaniment is produced in a tone color not suitable to the rhythm pattern generated by the auto rhythm system. To avoid this, it is necessary to provide a tone color selection switch and a tone signal source for the accompaniment, which however increases the manufacturing costs.
FIG. 3 shows a performer's panel of one conventional electronic musical instrument. With this electronic musical instrument, the performer first selects a rhythm through a rhythm selection switch (not shown), and subsequently selects one of piano, electric piano, jazz guitar, solid guitar and brass tones by depressing a corresponding one of the buttons for special preset which are shown at the center of FIG. 3. Then, the performer selects the rhythmic chord by depressing a button indicated by "rhythmic chord". FIG. 4 shows a performer's panel of another conventional electronic musical instrument. With this electronic musical instrument, the performer first selects a rhythm through a rhythm selection switch (not shown), and subsequently selects a tone color with respect to each of two rhythm patterns corresponding to the selected rhythm. More specifically, two rhythm patterns can be simultaneously generated in this electronic musical instrument, and one of piano, jazz guitar, solid guitar and phaser tones is selected for one of the two rhythm patterns, and one of brass, jazz guitar, solid guitar and phaser tones is selected for the other of the two rhythm patterns.
Thus, with the automatic accompaniment playing systems of he conventional electronic musical instruments, a tone color of tones of an accompaniment to be produced has been determined irrespectively of the type of the accompaniment (i.e., irrespectively of whether the accompaniment chord is a rhythmic chord or a melodic chord (an arpeggio)). It is, however, desirable to change the tone color in accordance with the type of the accompaniment.